No need to get philosophical. I thin Big Mac is asking a good question.

When XP released this feature, I heard noise fro the Mac community about how it would be cool to have but would suck up resources. I've heard XP users echo this.

I'll put it like this...On an average G4 Mac (600-800mhz) with 512MB of RAM how badly would your user session be affected if the other user had been running IE, Word, Mail, and iCal before you switched users? (as I understand it, these processes would still be running in the background)

How much worse would it be if the other user had also been running PhotoShop? Is the performance hit enough to notice?

Maybe if you didn't have a clue, you should have not posted in the first place.

I know you're a little slow, so I'll repeat what I said above for your benefit:

THE QUESTION WAS ASKED IN SUCH A MANNER THAT IT IS IMPOSSIBLE TO PROVIDE A GOOD ANSWER FOR IT.

Had more information been given (examples were provided in my original reply), he might have gotten a better answer.

Quote:

Now, lets end this pissing contest, okay? Okay.

I had no intention of starting a pissing contest with you, jackass. I was soliciting more information. Perhaps if you had nothing better to contribute than a smart-assed comment to my reply, you shouldn't have posted.

I have no experience with Panther but I use XP's fast user switching daily.

Running lots of apps on a login that isn't active can take up resources, but I haven't noticed it to be much of a problem.

I'll regularly leave Outlook Express, Mozilla and Word running while my fiancee switches to her login to check her e-mail or play PopCap games. No real slowdowns on the 800mhz Duron running , that's to say nothing of the 2.8ghz P4 the proctors share at work.

As far as restarts, you are warned that other users are still logged in and apps are running and told you should make sure everything is copasetic with those accounts before restarting.

What he was presumably asking is: assume the system takes up 150 Megs, and one user's apps take up another 200 Megs. With another user running the very same apps, how much more RAM is required? Just another 200? Less, because some is shared? More, because the system requests more?

Moose: The question could have been more technically accurately asked, but instead of even attempting to provide a) a reasonable answer, b) an explanation of why the question was vague, c) provide an example where the question could be answered clearly... well... stop.

Feature resource use: I would expect it isn't memory intensive at all, it's just spawning new apps/threads.

Paging: It will depend completely on how much RAM you have. *One* user will cause a low-RAM system to page heavily with moderate use. 4GB of RAM, and you could probably have half a dozen people simul-logged on without problem.

Essentially, your RAM use will be whatever user A is doing + whatever user B is doing. If you have enough RAM to prevent page thrashing with that total, then you're good to go.

I would guess that except for the overhead to run another system (it wouldn't all be shared memory for security issues) then it would be just like opening another app in your own space. If you have 10 apps open, and then you open BBEdit, no problem, so if user A has 10 apps open and user B opens BBEdit, I don't see how it would be different.

If user A's apps aren't idle though, that may be another story and I expect the slowdown tot he system would be the same as if you were logged in as that user (unless X will lower their priority compared to yours).

Some interesting replies, to say the least. I'm sorry I caused a conflict because I wasn't specific enough before. Most knew what I meant, though. . .

After reading through the replies and giving it some thought, it now makes sense that running the same tasks on two accounts would cause the memory footprint to grow to around twice the amount it would have been with only one open account. I was thinking, perhaps, that the account(s) in the background could have additional portions of their resources paged-out. But since these are true concurrent log-ins, they wouldn't be treated differently from the foreground account.

The headline is absolutely wrong. Apple isn't patenting anything close to user switching, or multiple user accounts. Instead, what they're patenting is a technology similar to, or based off, Location Manager, for mobile devices - such as a future iPod.

Experience shows that under "normal" lite use (Various IM clients, Web browsers, and email) that XP's user switching works fine, 256MB on a 366Mhz Celeron, for 3 users in my experience. It works and works well, I'd expect OS X to be about the same...

---

As for Panther, as long as a regular user can't restart/shutdown the system while an Administrator account is logged on and running an application I'm happy. Or it maybe ok if your not running anything, it should be an option allowing you to select what apps would require your ok to let others interrupt without your ok, or not. For example mail.app is ok to end, but Final Cut is not. No reason why your kids should be able to log you out and interrupt what your doing...

I've never used Panther before, but I have used fast user switching in XP. Well, it's actually not that fast. You have to go to Start > Log Off, then you click switch user. Basically it goes back to the main screen, and it tells you if the person is logged on, and what apps they are running. It is kind of faster to switch users this way, but it doesn't look nearly as fast as Apple's way.

As far as performance goes...the computer is a Dell 2GHz Pentium 4, 256MB RAM, 30GB HD...so it's not exactly the fastest computer in the world. But the performance when logged on to another account doesn't seem to take that much of a hit. I figure that the performance loss in OS X will be not nearly as bad, considering how well the OS handles multitasking.

In XP, you can fast user switch by pressing the window's key and L at the same time. It's considerably faster than a logout which requires that the apps all quit which can take a long time. It also saves you a seemingly VERY slow login afterwards.